NEWBURYPORT — In the middle of holding my headstand, I reminded myself to engage my forearms, relax my breath, and take in the surroundings from this new perspective. Normally a position I am quite familiar with — having integrated it into my yoga practice a few years ago — this time things were different.

Instead of being on my mat, supported by the steady earth below, I was in the middle of what looked like a bigger, wider surfboard. If my center of balance shifted too much in any direction, I was going down. Down into the cool water of Joppa Flats, a serene salt marsh with a soft current nestled along the western edge of the Merrimack River leading toward Plum Island in Newburyport.

It had been my first trip to Joppa Flats, and only the third time I was heading to a body of water armed with a 10-foot, 35-pound, stand-up paddleboard under one arm and a 9-foot carbon-fiber paddle in my other hand.

As an avid yoga practitioner, it was only a matter of time before I would learn about one of the fastest-growing water sports: stand-up paddleboarding, or SUP. Nowadays, it is quite common to see people, including yoga practitioners, flocking to local outfitters, sporting goods stores, and recreation departments for a chance to try “walking on water.”

Parks and recreation departments in Billerica and Westford are teaming up with Vermont-based Still River Outfitters, which has a location in Lowell, to offer summer SUP classes to residents. Outfitters such as Newburyport’s Plum Island Kayak
and Marblehead’s Little Harbor Boathouse are seeing more customers renting stand-up paddleboards than kayaks.

“We started offering stand-up paddleboards two years ago and it took off quick,” said Ken Taylor, owner of Plum Island Kayak. “Our business is about 80 percent touring and 20 percent rentals, and stand-up paddleboards have surpassed kayak rentals already.

“Where there is water, there is an opportunity to SUP,” he added. “That’s the beauty of it. It’s not just for a certain group of people, like surfers, but it’s open to anyone of any ability and you can make it as hard or easy as you want.”

Stand-up paddeboarding, or paddlesurfing, can be traced to Hawaii, where it originated as one of the first forms of surfing. The sport reemerged in the 1960s when surf instructors would simply stand on their boards to take photographs. Surfers would use the technique to paddle further and catch waves in a set because they had a better view.

Once the first stand-up paddleboard — the Cruise Control All Around
developed by custom surf shaper Jimmy Lewis — was introduced on the mainland, the sport took off.

Nearly a year after my serene experience at Joppa Flats, I was back in Newburyport, in the lobby of Plum Island Kayak, looking at Taylor’s computer screen as we speculated about
wind and tide conditions.

The afternoon was sunny, the air mild, when Taylor and I selected a soft-top 11-footer with a wide base. “This way, you’ll have more stability if the water is choppy,” he told me. Once at the launch, as the rest of Taylor’s staff unloaded a group of more than 40
Boy Scouts returning from a kayaking excursion, we saw the wind whip the Merrimack into choppy, short waves.

It was a far cry from the smooth current of Joppa Flats, and I decided my SUP skills were not so honed as to attempt the mighty Merrimack just yet.

Taylor’s son, Sam, however, was up for the challenge, as he and co-worker Jimmy Conway took two SUPs out on the water for a short-lived and wobbly ride. Sam stayed on his knees while Conway successfully stood up twice before paddling back to shore.

While Taylor’s crew needs to plan SUP tours around the tide, Maryellen Auger, owner of Little Harbor Boathouse in Marblehead, isn’t as concerned with weather conditions.

Auger’s office, opened in 2008, leads out to a private park about 50 yards away from the water. Auger’s paddlers can enjoy the view of Salem Sound and its two islands, or head over to Brown Island or even around it to Marblehead Harbor, providing entertainment to onlookers dining at the many outdoor restaurants in town.

Auger’s fleet features 18 SUPs, with four premium boards for more experienced paddlers.

“They’re more expensive and made from different material, so not as forgiving, so you need a better familiarity with being on the board,” said Auger. “The wonderful thing about the sport is anyone can do it, any age or fitness level. We have larger boards to accommodate larger, heavier people and we have boards for smaller frames and separate kids’ boards.”

Like Plum Island Kayak, Auger’s paddleboard rentals have surpassed her kayak rentals since the SUP program was launched three years ago.

“There is a fitness component that just isn’t there with kayaking,” she said. “Kayaking is a workout, but stand-up paddleboarding is just different. It’s also tremendously social. It’s like going for a long walk with a friend and having a good conversation, except you’re walking on water now.”